#include <stdio.h>
int main()
{
	freopen("zz_test\\test1.in", "r", stdin);
	freopen("zz_test\\test1.out", "w", stdout);
	int wei = 0;
	scanf("%d", &wei);
	double money = 0.2;
	if ( wei > 30 ) {
		printf("Fail");
	}
	else if ( wei > 20 ) {
		money += wei * 0.7;
	}
	else if ( wei > 10 ) {
		money += wei * 0.75;	
	}
	else {
		money += wei * 0.8;
	}
	if ( wei <= 30 ) {
		printf("%.2lf", money);	
	}
	return 0;
} 
